BMC-side state machine details

ONLY ONE BLOB IS ALLOWED OPEN AT A TIME

To avoid excessive complications, there is a restriction that only one blob within the firmware handler can be open at a time.

The system starts in the notYetStarted state.

At each state, each method has a specific effect, depending on a variety of details, and sometimes the behavior is consistent regardless of overall state.

Opening the active image or hash always fails:

• open(/flash/active/image) returns false -- file cannot be opened.
• open(/flash/active/hash) returns false -- file cannot be opened.

The two files are only present once their corresponding blob has been opened.

notYetStarted

The starting state.

• open(/flash/image)
• open(/flash/tarball)
• open(/flash/hash)
• open(/flash/verify)
• open(/flash/update)

uploadInProgress

The BMC is expecting to receive bytes.

• open(/flash/*) returns false because fileOpen == true

• close(/flash/*) triggers state -> verificationPending

• commit(/flash/*) returns false

verificationPending

The BMC is ready for verification or more bytes.

• open(/flash/image) triggers state -> uploadInProgress

• open(/flash/tarball) triggers state -> uploadInProgress

• open(/flash/hash) triggers state -> uploadInProgress

• open(/flash/verify)

• open(/flash/update)

• commit(/flash/verify) state -> verificationStarted

verificationStarted

The verification process has started, no more writes allowed.

• open(/flash/*) returns false because state == verificationStarted

• close(/flash/verify) state -> verificationCompleted

verificationCompleted

The verification process has completed.

• open(/flash/image)
• open(/flash/tarball)
• open(/flash/hash)
• open(/flash/verify)
• open(/flash/update)

updatePending

The update process is pending.

updateStarted

The update process has started.

• open(/flash/*)r eturns false because fileOpen == true

updatedCompleted

The update has completed (optional state to reach)

Expected State Transition Sequence

Action	Before	After
1. getBlobList()	NYS	NYS
2. stat(/flash/image)	NYS	NYS
3. open(/flash/image)	NYS	UIP
4. write(...)	UIP	UIP
5. close(/flash/image)	UIP	VP
6. open(/flash/hash)	VP	UIP
7. write(...)	UIP	UIP
8. close(/flash/hash)	UIP	VP
9. open(/flash/verify)	VP	VP
10. commit(...)	VP	VS
11. sessionStat(...)	VS	VS (if !completed)
11. sessionStat(...)	VS	VC (if completed)
12. close(/flash/verify)	VC	UP
13. open(/flash/update)	UP	UP
14. commit(...)	UP	US
15. sessionStat(...)	US	US (if !completed)
15. sessionStat(...)	US	UC (if completed)
16. close(/flash/update)	UC	NYS